Fig. 7: The efficient value-added of lignin to biopolyester can be achieved by constructing stable engineering strains through genome integration functional modules.

a Differences in vanillic acid metabolism between the genome integration strains H16Q1, H16Q2 and H16Q3. b Analysis of biomass changes and substrates metabolism during the cultivation of H16Q3 with vanillin as the sole carbon source. Gray represents vanillin, and purple represents vanillic acid. c Analysis of the growth curve and material changes of the H16Q4, which contains two copies of vanAB in its genome, during cultivation with vanillin as the sole carbon source. Gray represents vanillin, and purple represents vanillic acid. d Tolerance of H16Q4 to different concentrations of vanillin. Growth curves of H16Q4 with 7.5 mM (violet), 10 mM (gray), 12.5 mM (green), 15 mM (purple) and 17.5 mM (pink) vanillin as the sole carbon source. e Analysis of tolerance and metabolic capacity of laboratory directed evolution strain (H16Q5) to different concentrations of vanillin. f Differences in PHB accumulation between H16Q1 and H16Q5 in high concentrations of aromatic compounds as substrates. Vanillin was used as the sole carbon source in the PHB accumulation phase, and the fermentation culture was carried out using batch replenishment. The vanillin concentration was 20 mM at the initial and each replenishment, and the replenishment time was 24 h, 48 h and 72 h, respectively. In addition, a supplemental nitrogen source was required once at 48 h of fermentation to enhance the conversion of aromatic compounds (1 g/L). In addition, metabolite concentrations in the media were measured using HPLC-UV_VIS. Error bars illustrate the standard deviation of three biological replicates. The data are the mean ± SD, n = 3. VAN vanillin, VA vanillic acid. Source data are provided as a Source Data file.